Fusible cut-out



(No Model.)

I. N. MILLER.

PUsIBLB CUT-OUT. No. 430,967. Patented June 24, 1890.

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UNITED STATES PATENT OFFICE.

ISAAON. MILLER, OF CINCINNATI, OHIO.

FUSIBLE CUT-OUT.

' SPECIFICATION forming part of Letters Patent No. 430,937, dated J une 24, 1890.

Application filed March 13,1890. Serial No. 343,724. (No model.) y

` State of Ohio, have invented certain new and useful Improvements in Electric Safety Cut- Offs and Switches, of which the following' is a specification.

My invention relates ,to a safety device adapted to automatically cut out or switch an electric circuit, or a portion of it, when it accidentally becomes unduly charged, either from electric light currents, lightning, or other unusual electrical disturbances that are dangerous in their character. Another object of my invention is to provide a device that will satisfactorily do the work without the use of an electro-magnet, so as to automatically open a circuit in one or bot-h directions. Another object of my invention is to so connect the device in circuit that when an undue current is brought into circuit it will automatically open the same in one direction and ground it in the other without the use of an electro-magnet. Another object of my invention is to provide a device that will automatically open both sides of a loop-circuit in one direction and connect the two opposite sides together, so as to preserve the continuity of the through-circuit and cut out the loop automatically and without the aid of an electro-magnet, all of which will be fully set forth in the description of the accompanying drawings, making a part of this specification, in Which- Figurel is a side elevation of an automatic switch or single cut-off for a terminal oiiice.

Figure 2 is a side elevation of a double auto-v matic switch or cut-off for an intermediate oiice.

The diagram Fig. l shows the arrangement foranormally-closed circuit of a singlewire protector or safety device, which is operated through the switch-lever D, which is normally connected in circuit through the post L, Wire A, post K, leading from wires a to wire b and binding-post c to instrumentwire d.

B represents a coiled-wire spring normally tending to pull the lever D down upon the post F, which has a secondary connection by wire e to the binding-post f and ground-wire g. The wire A is made of easily-fusible metal, preferably German silver wire-say No.. 30- one end of which is attached to the post K and the other to the switch-lever D.

The operation of this safety device is as follows: If a lightning discharge or electriclight current or other current of higher tension than that which is normally required for ordinary telegraphic or telephonie purposes is communicated to the line, the passage of this undue current through the wire A melts it. Then the spring B pulls the movable lever D down upon they stop-post F, when the circuit is connected through wire e and pointpost f to wire g, cutting out the wire d, which ordinarily runs to an instrument, and thereby avoiding both danger to the operator and setting re to the building. In Fig. 2 I have shown two protectors arranged for an ordinary loop-connection of a closed circuit, the operation of which is as follows: I represents the line-wire coming to post 2, thence by wire a to post L, lever D, Wire A, post K, wire I), post c, and wire cl, thence to the instrument, and back through the second protector, as follows: from post 3 by wire 4, post K, wire A, lever D, post L, Wire a, to post 2 and line-wire M. Now in case the wires A of the instrument are melted, as before described, the circuit will be through the post F by contact of the switch-lever D, the same as shown in Fig. l, the only difference being that the cnice-instruments are connected between two protectors, so that the loop will never be left open by the action of either or both protectors. For example, if No. l only should act, the circuit would be left open between the protector an d the instrument, but closed on the' line through the post F, wire c, post f, Wire h, to post 2 of the second protector. If the second protector only should act, the same results would follow. If both protectors act at the same time, the circuit would be complete, but both sides would be open between the protectors and the instrument. When only one protector acts, one side of the circuit between it and the instrument is closed. If there should be any escape in the office where the instrument is lo` cated, or the electric light or foreign current has sufficient potential to form an arc to a ground or. other Wire connected to the IOO same switch-board,then the second protector would act and both wires be opened between the protectors and the instrument or switch, but the through-circuit on the line will be kept closed.

I believe I am the iirst to employ a device connected in circuit and of the construction described, that protects an office or building from electric-light currents by opening the circuit automatically and without the aid of an electro-magnet, so as to disconnect said office or building and at the same time preserve the continuity of the through-circuit. This is a point ot" the greatest value for protecting telegraph and other wires which are connected with a number of intermediate ofiices. By placing a single protector at each terminal of a wire and a double protector at eaelrintermediate office the eitect of an electric-light current would be to cut the intermediate offices out of the circuit and leave the circuit continuous from one terminal to the other. The wire can then be operated again as soon as the electric-light current disappears byrestoring the two terminal protectors to their proper condition.

In devices-hitherto used the circuit at the intermediate stations is left open or grounded by the action of electric-light currents, instead of closed and in its normal condition, thus greatly delaying the restoration of the circuit to its normal or proper working condition. Many intermediate oftices are closed at night and on Sundays. If, therefore, a device tor protecting such oiiices against the dangerous eifects of electric-lightand lightning currents leaves the circuits open, said circuits will remain open for want of attention, thus rendering the wire or wires useless.

I claim for my invention a device that can be used at pleasure to leave the circuit open in both directions, or in only one direction,

the wire in the opposite direction being grounded, and which will also open two sides of a loop in one direction and close the two wires in the opposite direction, thus combining three valuable qualities in one device.

I do not claim as new or original with me the principle of using a fusible wire or metal foil for breaking the continuity of a circuit, as that principle has been in daily use for many years.

That I claim as new, and desire to secure by Letters Patent, is-

In an automatic electric protector, the combination of two movable switch-levers D, arranged on opposite sides of the instrument to be protected and each connected with the main line, the posts F, adjacent to the free ends of the switch-levers and connected crosslwise to the opposite sides of the main line,

the posts K, connected with theline and the instrument, the fusible wires A, connecting said posts with the switch-levers, and the springs B to pull the switch-levers in contact with the posts F when the wires A are fused, substantially as described.

In testimony whereof I have hereunto set my hand.

ISAAC N. MILLER. Xi'vitiiesses:

T. SIMMONS, C. W. MILES. 

